Table 1 Sample characteristics
|  | n | Sample with data on ASD traits n = 3938 | n | ASD diagnoses sample n = 56 | n | ADHD diagnoses sample n = 194 |
|---|---|---|---|---|---|---|
Child characteristics | ||||||
 Gender (% boys) | 3938 | 50.0 | 56 | 85.7 | 194 | 63.9 |
 Gestational age at birth (weeks) | 3926 | 39.85 (1.81) | 56 | 39.17 (2.57) | 194 | 39.74 (2.17) |
 Ethnicity | 3933 |  | 56 |  | 194 |  |
  Dutch % | 2771 | 70.5 | 43 | 76.8 | 121 | 62.4 |
  Other Western % | 358 | 9.1 | 3 | 5.4 | 20 | 10.3 |
  Non-Western % | 804 | 20.4 | 10 | 17.9 | 53 | 27.3 |
 CBCL 1.5–5 total score | 3665 | 18.11 (13.28) | 51 | 29.91 (20.80) | 176 | 32.10 (18.41) |
 BRIEF-P (executive functioning) total score | 3901 | 85.28 (15.65) | 56 | 108.07 (26.72) | 189 | 104.35 (19.85) |
 Inhibition | 3886 | 22.22 (5.09) | 56 | 28.69 (7.55) | 187 | 28.82 (6.39) |
 Shifting | 3930 | 13.67 (3.34) | 56 | 18.36 (5.67) | 193 | 15.47 (4.34) |
 Emotional control | 3932 | 14.24 (3.48) | 56 | 18.20 (5.18) | 193 | 17.27 (4.46) |
 Working memory | 3892 | 21.55 (4.79) | 56 | 27.01 (8.96) | 191 | 26.38 (6.46) |
 Planning/organization | 3927 | 13.61 (2.96) | 56 | 15.80 (4.15) | 192 | 16.42 (3.59) |
 SRS (ASD traits) scorea | 3938 | 0.21 (0.23) | 54 | 0.94 (0.64) | 169 | 0.50 (0.43) |
 TRF (ADHD traits) score | 2272 | 3.00 (4.73) | 34 | 7.50 (7.56) | 116 | 6.97 (6.66) |
Maternal characteristics | ||||||
 Education level | 3830 |  | 54 |  | 192 |  |
  Low % | 76 | 2.0 | 1 | 1.9 | 10 | 5.2 |
  Medium % | 1153 | 30.1 | 22 | 40.7 | 73 | 38.0 |
  High % | 2601 | 67.9 | 31 | 57.4 | 109 | 56.8 |
 BSI (psychopathology) score | 3612 | 0.62 (1.01) | 50 | 0.95 (1.29) | 174 | 1.24 (1.60) |